Improvement in steam-engines for rock-drills



V BRANDON.- Steam-Engine for Bock-Drills.

Patented May 25,1875.

ATTORNEY THE GRAPHIC GO.PHOTO-LITH.39&4X PARK FUCLNJC PATENT Orrroa.

JAMEs BRANDON, or new YORK, N. Y.

IMPROVEMENT lN STEAM-ENGINES FOR ROCK-DRILLS.

I Specification forming part of Letters Patent No. 163,631, dated May 25, 1875; application filed October 31, 1874.

To all whom it may concern.-

Be it known that 1, JAMES BRANDON, of the city, county, and State of New York, have invented a new and useful Improvement in Steam-Engines for Rock-Drills, of which the following is a specification:

This invention relates to the construction of engines for driving rock-drills, more especially, but which may be applied to other purposes; and consists in the arrangement of the steam passages and ports in the steam-chest.

Figure 1 is a vertical longitudinal section of an engine constructed according to my invention. Fig. 2 is a top view of the steamchest with the valve taken ott'. Fig. 3 is a detail, showing the mode of introducing steam into the chest for operating the valve.

Similar letters of reference indicate corresponding parts.

0 is the steam-cylinder. A and B are steampassages. G is the exhaust-port. P P represent the main piston. L is the steam-chest, having its ends accurately bored out and two plugs or pistons, K K, titted to the same,.and forming the valve V. The steamchest L has grooves turned out of the bore, as shown at n n. The pistons K K have grooves a a, having communications or passages m 1' and m 0". H is a passage communicating with the inte rior of the main cylinder, and terminating in the steam-chest at W. E is a steam-passage which communicates with the interior of the main cylinder, and terminating in the steamchest at N. v H is a passage which communicates with the interior of the main cylinder, and terminates in the steam-chest at Y. E is a steam-passage which communicates with the interior of the main cylinder, and terminates in the steam-chest at M.

With this arrangement of the ports and steam-passages, we will assume that the piston P P is passing from left to right, and that it has passed far enough to just commence to open the passage H, the part P of the main piston being just long enough to close the pas sage E. The steam will now pass through the passage H W, and, through 4 j at, will move the valve piston K K, carrying with it the slide-valve V. The exhaust from the other end of the steam-chest will pass through M E into the main cylinder, along between the parts P P of the main piston to I, and will exhaust at O. The grooves n n in the steam-chest are so arranged in connection with the grooves a a in the valve-piston that when the slidevalve V is just over the ports A and B the small piston will have passed so far that the communication between the groove a in the steam-chest and the groove to in the valve-piston K will be just closed at the same time the groove to of the passage n will be just opening. Now, it will be seen that the steam passing through H W will have full pressure until the piston K closes the passage by its own movement. The steam cannot pass out through N E, the part P of the main piston having covered E; consequently the valve-piston K K will still have the expansion of the steam to carry it over; nor can the steam escape until the passage E is opened by the main piston P, as it moves back from right to left, and in a similar manner when the piston passes in the other direction.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- The valve-piston K K, having grooves a a and passages m m r 7', combined with a steamchest, L, having grooves n n M N W Y and passages H H E E, as and for the purpose specified.

JAMES BRANDON.

Witnesses:

T. B. lVIOSHER, ALEX. F. Ronnnrs. 

